WASHINGTON — More than 200,000 people signed up for coverage in the first two weeks after President Joe Biden re-opened HealthCare.gov as part of his coronavirus response, the government said Wednesday. The solid start to the three-month special enrollment period indicates a pent-up demand for health insurance as the COVID-19 pandemic approaches the one-year mark and many people remain unemployed or unable to work as many hours as they did before the outbreak. HealthCare.gov offers subsidized private health insurance under the Obama-era Affordable Care Act, catering mainly to low- and moderate-income working people. If Congress passes Biden’s coronavirus response bill, taxpayer-funded financial aid will become considerably more generous, and a greater number of solid middle-class households would also qualify for assistance.